Issue 1/2004 (No. 23)
AmiBroker Tips newsletter.
Issue 1/2004. No 23.
20 September 2004.
Copyright (C)2004 AmiBroker.com.
All back issues available from:
http://www.amibroker.com/newsletter/

IN THIS ISSUE

1 Welcome
2 How to use new 'drag and drop' features in AmiBroker

Welcome

Welcome to the 1st issue of AmiBroker Tips newsletter in the 2004. Well ...you have probably forgotten about newsletter at all, the last issue was back in 2001 but I think it is good idea to "re-incarnate" the newsletter. I think that this will be good place to introduce new features added in each beta and you will gain additional source of information (other than Read-Me files coming with beta versions).

Just a reminder: if you have any comments/suggestions or article ideas, please don't hesitate to drop a line to newsletter@amibroker.com

How to use new 'drag and drop' features in AmiBroker

Introduction

AmiBroker 4.62.1 allows you to easily create and modify your indicators with few moves of a mouse. From now on you can build sophisticated indicators without any programming knowledge at all. The available (ready-to-use) indicators are listed in Charts tab of the Workspace window.

There is a video tutorial at: http://www.amibroker.net/video/dragdrop1.html that shows basic usage of new drag and drop functionality.


How to insert a new indicator.

To display a new indicator in a separate chart pane just find the indicator in the list (in Workspace -> Charts) and double-click on the indicator name. As a result new indicator pane will be created and Parameters dialog will be displayed. Here you can change the properties of the indicator (like color or periods). To accept the settings press OK button. (you will find the detailed description of parameters window below).
Example:
To insert RSI pane - find RSI indicator in the list, double-click on the name, select the number of periods and color, then press OK.



How to delete the indicator.

To remove the indicator, press Close button from the menu on the top right-hand side of the indicator pane (the menu will be displayed if you place the mouse cursor in the nearby). This menu allows you also to move the indicator pane up/down or maximize the pane.


You can also use Close command from context menu that shows up when you click on the chart pane with right mouse button.


How to overlay one indicator on another indicator.

To overlay one indicator on another one, press LEFT mouse button on the indicator name, drag (with mouse button held) the chosen indicator into the destination pane and release the button.
Example:
To insert another RSI (based different periods number) into the same pane - drag RSI into the previously created RSI pane, change the number of periods in the Parameters window and press OK



How to remove the indicator plot from the pane.

To remove one of the indicators displayed in the indicator pane - click with RIGHT mouse button on the chart title (near the top of chart pane) and select the indicator that you want to remove.



How to change parameters/colors/styles of indicators.

The Parameters window allows you to change parameters, colors and styles of your indicators. Parameters window is displayed when you insert a new indicator. You can also click RIGHT mouse on the chart pane and choose Parameters from the context menu. Parameters window displays all the parameters defined in AFL code of certain indicators (also user-defined parameters) so it's contents depends on the indicator chosen. However - for most of the indicators you will see:


How to overlay indicators with different scales.

To have in one pane two (or more) indicators that use different scaling, drag the second indicator onto the first one, in Parameters window click on Style field and check StyleOwnScale setting.
Example:
Drag OBV (On Balance Volume) into RSI pane. Then define style as styleOwnScale. As a result - both indicators are visible and properly displayed.



How to create an indicator based on another indicator.

AmiBroker allows you also to easily create indicators based on values of another indicator. All you need to do is to press LEFT mouse button on the indicator name, drag (with mouse button held) the chosen indicator into the destination pane and release the button. As a result - the indicator will be placed in the existing chart pane. In the parameters dialog Price field parameters indicates what base values are used to calculate the indicator.
Example:
To calculate Simple Moving Average of previously created RSI indicator, drag the MA indicator into RSI pane. The contents of "Price Field" parameter indicates, that Moving Average is calculated out of RSI(15) values. (See the below picture).



Using Param(), ParamColor(), ParamToggle(), ParamStyle() functions (for advanced users).

These functions, when used in formula, allow you to change indicators' settings directly from Parameters window.


Param( (''name'', defvalue, min = 0, max = 100, step = 1, sincr = 0 )
Adds a new user-definable parameter, which will be accessible via Parameters dialog.
ParamColor( ''name'', defaultcolor )
Adds a new user-definable color parameter, accessible via Parameters dialog. ParamColor function allows you to use colorCycle as a default value. When you use colorCycle parameter, default color cycles through red, blue, green, turquoise, gold, violet, bright green, dark yellow, when you insert your indicators into the same pane.


ParamStyle(''name'', default = styleLine, mask = maskDefault ) - allows to select the styles applied to the plot from the Parameters window. Apart from styles available in previous versions of AmiBroker, there are two new style constants: The list of available styles displayed in the Parameters window depends on the mask parameter.
ParamField(''name'', field = 3 ) - allows to pick the Price field for the indicator (field which is used to calculate values of the indicator). Function returns the array defined by field parameter. Default value = 3 returns Close array. The possible values of field parameter are:
ParamToggle(''name'',''values'',default=0 ) - function that allows to use boolean (Yes/No) parameters.

_


Example:

The below indicator allows you to check how the parameters work in the custom code. You can change settings from Parameters dialog.

Buy = Cross(MACD(), Signal() );
Sell = Cross(Signal(), MACD() );

pricefield =
ParamField("Price Field", 2);
Color =
ParamColor("color",colorRed);
style =
ParamStyle("style",styleLine,maskAll);
arrows =
ParamToggle("Display arrows", "No|Yes",0);
Plot(pricefield,"My Indicator",Color,style);
if(arrows)
{
  
PlotShapes(Buy*shapeUpArrow+Sell*shapeDownArrow,IIf(Buy,colorGreen,colorRed) );
}

 

Special functions: SECTION_BEGIN, _SECTION_END, _SECTION_NAME, _DEFAULT_NAME, _PARAM_VALUES explained
(for advanced users only)

These are new functions that are used by drag & drop mechanism. The most important pair is _SECTION_BEGIN("name") and _SECTION_END().

When you drop the formula onto chart pane AmiBroker appends the formula you have dragged at the end of existing chart formula and wraps inserted code with _SECTION_BEGIN("name") and _SECTION_END() markers:

So, if original formula looks as follows:

P =
ParamField("Price field",-1);
Periods =
Param("Periods", 15, 2, 200, 1, 10 );
Plot( MA( P, Periods ), _DEFAULT_NAME(), ParamColor( "Color", colorCycle ), ParamStyle("Style") );

it will be transformed by AmiBroker to:

_SECTION_BEGIN("MA");
P =
ParamField("Price field",-1);
Periods =
Param("Periods", 15, 2, 200, 1, 10 );
Plot( MA( P, Periods ), _DEFAULT_NAME(), ParamColor( "Color", colorCycle ), ParamStyle("Style") );
_SECTION_END();

_SECTION_BEGIN/_SECTION_END markers allow AmiBroker to identify code parts and modify them later (for example remove individual sections). In addition to that sections provide the way to make sure that parameters having the same name in many code parts do not interfere each other. For example if you drop two moving averages the resulting code will look as follows:

_SECTION_BEGIN("MA");
P =
ParamField("Price field",-1);
Periods =
Param("Periods", 15, 2, 200, 1, 10 );
Plot( MA( P, Periods ), _DEFAULT_NAME(), ParamColor( "Color", colorCycle ), ParamStyle("Style") );
_SECTION_END();

_SECTION_BEGIN("MA1");
P =
ParamField("Price field",-1);
Periods =
Param("Periods", 15, 2, 200, 1, 10 );
Plot( MA( P, Periods ), _DEFAULT_NAME(), ParamColor( "Color", colorCycle ), ParamStyle("Style") );
_SECTION_END();

Note that code and is parameter names are identical in both parts. Without sections the parameters with the same name will interfere. But thanks to uniquely named sections there is no conflict. This is so because AmiBroker identifies the parameter using section name AND parameter name, so if section names are unique then parameters can be uniquely identified. When dropping indicator AmiBroker automatically checks for already existing section names and auto-numbers similarly named sections to avoid conflicts. Section name also appears in the Parameter dialog:

Last but not least: you should NOT remove _SECTION_BEGIN / _SECTION_END markers from the formula. If you do, AmiBroker will not be able to recognize sections inside given formula any more and parameters with the same name will interfere with each other.

_SECTION_NAME is a function that just gives the name of the function (given in previous _SECTION_BEGIN call).

_DEFAULT_NAME is a function that returns the default name of plot. The default name consists of section name and comma separated list of values of numeric parameters defined in given section. For example in this code:

_SECTION_BEGIN("MA1");
P =
ParamField("Price field");
Periods =
Param("Periods", 15, 2, 200, 1, 10 );
Plot( MA( P, Periods ), _DEFAULT_NAME(), ParamColor( "Color", colorCycle ), ParamStyle("Style") );
_SECTION_END();

_DEFAULT_NAME will evaluate to "MA1(Close,15)" string.

_PARAM_VALUES works the same as _DEFAULT_NAME except that no section name is included (so only the list of parameter values is returned). So in above example _PARAM_VALUES will evaluate to "(Close, 15)" string.


Frequently Asked Questions about drag & drop functionality

Q. I can not see buy/sell arrows from my trading system

A. Starting from version 4.62.1 trade arrows can be displayed on any chart pane (not only one built-in price chart). However, by default, the arrow display is turned OFF.
To turn it ON you have to open Indicator Builder or choose "Edit Formula" from the chart context menu and check "Show Arrows" box.

 

Q. The read me says: "Automatic Analysis formula window is now drag&drop target too (you can drag formulas and AFL files onto it)". What does it mean?

A. It means that you can drag the formula from either Chart tree or .AFL file from Windows Explorer and drop it onto Automatic Analysis (AA) formula window and it will load the formula into AA window. This is an alternative to loading formula via "Load" button in AA window.

Q. I can see version 4.62.0 listed in the Read Me but I did not see the announcement on AmiBroker mailing list ?

A: Version 4.62.0 was an internal beta version not available to the public. 4.62.1 is the first public beta with new drag and drop features.

Q. Can I drop a shortcut onto the formula window ?

A: No you can't. You can only drag & drop files with .AFL extension (shortcuts in Windows have .lnk extension).

Q. Can I add my own formulas to the Chart tree ?

A. Yes you can. Simply save your .AFL formula into Formulas subfolder of AmiBroker directory and it will appear under "Charts" tree (View->Refresh All may be needed
to re-read the directory)

Q. I have added new file to the Formulas folder, but it does not show up in the Charts tree unless I restart AmiBroker? Is there a way to refresh Chart tree ?

A. You can refresh Chart tree by choosing View->Refresh All menu.

Q. If I modify the formula that ships with AmiBroker will it be overwritten by next upgrade?

A. Yes it will be overwritten. If you wish to make any modifications to the formulas provided with AmiBroker please save your modified versions under new name or (better) in your own custom subfolder.

Q. I can see Reset All button in Parameters dialog but it sets all parameters to default values. Is there a way to reset SINGLE parameter ?

A. No, there is no such option yet, but it will be added in upcoming betas.

Q. I dragged RSI to the price chart pane and got a straight red line at the bottom of the pane. What is wrong?

A. When you drop two indicators / plots that have drastically different values you have to use style OwnScale for one of it. You can turn on OwnScale style using Parameter dialog. This ensures that scales used for each are independent and you can see them properly. Otherwise they use one common scale that fits both value ranges that results in flattened plots.

Q. The light grey color of the new AFL special functions_SECTION_BEGIN etc makes them invisible in my bluegrey background IB color. How could I change the special functions color ?

A. Right now, you can't. But there will be a setting for coloring special functions in the next version.

Q. When I drop the indicator the Parameter dialog does not show all parameters. Is this correct ?

A. Yes it works that way. The idea behind it is simple. When you drop new indicator AmiBroker displays a dialog with parameters ONLY for currently dropped indicator. This is to make sure that newly inserted indicator parameters are clearly visible (on top) and new user is not overwhelmed by tens of other parameters referring to previously dropped indicators. On the other hand when you choose "Parameters" item from context menu then ALL parameters will show up - allowing you to modify them all any time later.

Q. My indicator list is full of names like "#96 MACD". Where does #96 come from ?

A. When you double click the item in the chart tree AmiBroker creates new chart pane and generates the formula for it. It also gives it a name in the format of #Number SectionName. #Number is the consecutive chart formula number (AmiBroker stores custom formulas internally in the array that is numbered). Section name comes from AFL file name used to generate this chart. The numbering allows to distinguish between different formulas based on the same original indicator. Note that this may change in the future versions.


AmiBroker Tips newsletter. Issue 1/2004. Copyright (C)2004 AmiBroker.com. All back issues available from: http://www.amibroker.com/newsletter/